Lunar Orbiting Cubesat Sensor Transport System Mike Seibert, Alejandro Levi, and Mitchell Paradis Graduate Students, Colorado School of Mines

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Lunar Orbiting CubeSat Sensor Transport System Mike Seibert, Alejandro Levi, and Mitchell Paradis Graduate Students, Colorado School of Mines

Concept Origin Notional Mission Evaluated Carrier Spacecraft Conceptual Design The 2018 Lunar Polar Prospecting (LPP) Workshop Objective: • Structure: Based on EELV Secondary generated a series of recommendations for Deploy a constellation of 6 sensor spacecraft in single Payload Adapter (ESPA) Grande. prospecting of lunar water. Recommendation 3 was polar low lunar orbit plane. • Propulsion: Monoprop system with 2.5 km/s for swarms CubeSats overflying polar regions at delta-V capability. altitudes below 20 km. Recommendation 3 also Cruise Phase: Includes 179 m/s for 110 days of recommended “a swarm of hundreds of low cost LOCuST is released from the launch vehicle in a GTO. orbit eccentricity control impactors instrumented for volatile detection and A series of perigee maneuvers using carrier spacecraft • Earth Telecom: Optical derived from LADEE or quantification.” [1] propulsion are used to raise apogee to lunar distance. IRIS Version 2.0 radio • Relay Telecom: IRIS Version 2.0 (multiple if all RF) The graduate student team developed both mission Lunar Orbit Insertion/Optimization • Thermal control:Accounts for challenges of low and vehicle designs that address the LPP Lunar orbit capture into an initial 200km altitude orbit over lunar day side. recommendation during the Space Resources Design I polar orbit. Orbit is lowered to 10km altitude Main Propulsion course at the Colorado School of Mines in Spring perilune, 100km apolune. All capture and initial 2019. CubeSat optimization maneuvers use carrier spacecraft Deployers propulsion. The CubeSat swarm concept was interpreted to mean a constellation of small short mission duration Deployments spacecraft with sensors optimized for localizing After each deployment orbit phasing maneuvers to Solar Array surface water ice. To maximize useful life in low lunar adjust the true anomaly is performed at apolune. orbit, the team chose an approach with a larger Optical Communications Deployments of sensor spacecraft occur as rapidly as carrier spacecraft that deploys the swarm/ System every other orbit. The final constellation configuration constellation directly into low lunar orbit. has three sensor spacecraft leading the LOCuST Relay Antennas Not Shown Design Driving Requirements carrier spacecraft and three sensor spacecraft trailing. • LOCuST shall be ride-share compatible with Sensor Spacecraft Design Requirements nominal mission having LOCuST released into The constellation geometry is configured to have • Structure: CubeSat (1U to 12U) or Geosynchronous Transfer Orbit (GTO). ground tracks overlap as each sensor spacecraft 380mm ESPA port • Carrier spacecraft shall use standardized crosses 80° south latitude. The maximum time • Telecom: IRIS Version 2.0 with contingency deployment systems for sensor spacecraft between 80° crossings for overlap is a function of for low rate direct to/from Earth • Carrier spacecraft shall provide relay instrument field of view as shown below. communication communication for sensor spacecraft after • Propulsion: 100 m/s minimum for 60 days deployment. eccentricity control • Sensor spacecraft shall include relay communications with other sensor spacecraft. Advantages to LOCuST for Lunar CubeSats • Survive the Low Lunar Orbit (LLO) environment for • CubeSat propulsion can be optimized to extend a minimum of 90 days. CubeSat life in low lunar orbit. • LoCUST shall have a minimum capability of • CubeSat operations are simplified by removing the transporting six 6U CubeSat sensor spacecraft to Earth-Moon transfer, LOI, and orbit optimization LLO. from the concept of operations. • Removes the need for each CubeSat to carry deep space communications. LOCuST provides data relay as a service. • CubeSat operations begin in optimized Lunar orbit For a notional six spacecraft swarm with 2° field of allowing for initial remote sensing data to have view (FOV) sensors, initial coverage is complete after higher spatial resolution. half a lunar day. Majority coverage above 80°, including total coverage of PSRs after two lunar days. Future Design Extensions Surface Relay: The LOCuST carrier can provide relay overflights for assets on the lunar surface that do not have direct-to-Earth communication. Impactor deployment: The LOCuST carrier can be used to deploy impactors on an impact trajectory. The carrier can then serve as a data relay during impact events. References: [1] G. Morris and G. Sowers, “Lunar Polar Prospecting Workshop: Findings and Recommendations,” August 2018 Coverage south of 80° latitude from a 6 sensor spacecraft swarm with 2° FOV sensor. [2] Image Map of the Moon by T. M. Hare, R. K. Hayward, J. S. Blue, and (Ground swaths are to scale.) B. A. Archinal, Scientific Investigations Map 3316, Sheet 1 of 2, United Overview of LOCuST system operating in low lunar orbit. Half a lunar day (left) and two full lunar days (right). Earthrise image and CubeSat image credit: NASA Map image credit: USGS [2] States Geological Survey, 2015.